igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate for road bases, railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms prominent volcanic features like the Giant's Causeway.
Field identification & locations
Identify in the field by its dark color, heavy weight, and fine-grained texture lacking visible crystals; commonly found in volcanic regions worldwide.
